Three-dimensional articles can be replicated from a mold by repeatedly filling the mold with a material that can fill in all of the topological features of the mold, can be solidified, and then can be easily removed from the mold. Useful materials can include polymeric thermoplastic and polymeric thermosetting materials. Thermoplastic materials can be introduced into the mold cavity in a heated, flowable state and then can be solidified by cooling. Thermosetting compounds can be introduced into the mold as a liquid precursor and then cured to yield a solid replica. It is known to cure thermosetting compounds by a variety of means known to those of ordinary skill in the art including chemical reaction, thermal polymerization, UV-visible photopolymerization, or exposure to electron beam radiation.
The molds, commonly known as tools, can be produced by machining or they can be produced using alternate technologies discussed below. There is an interest in commercial and industrial applications to reduce the size of replicated articles and devices. A number of technologies have been developed to make molds for microreplication or nanoreplication of parts. These include using two-photon photochemistry to allow the selective solidification of individual volume elements (voxels) of a liquid resin system. Typically the systems employing this technology can make very high-resolution features over a small area. However two-photon photochemistry requires exposure to light sufficient to cause the photoinitiator to absorb at least two photons simultaneously. This requires a very high intensity pulse of radiation over a very short time and specialized equipment to produce these pulses.